The story of Homo luzonensis
Print Science Editor Scarlett Parr-Reid tells us what is known about Homo luzonensis, a newly discovered species of humans.
In the words of Yuval Noah Harari: “you could never convince a monkey to give you a banana by promising him limitless bananas after death in monkey heaven”. Aside from the fact that Yuval Noah Harari is a prolific author in the field of human evolution and twice won the Polonsky Prize for ‘creativity and originality’ for his work, what he said here, in his first book Sapiens, got me thinking a lot.
Human evolution is just as much by intention as it is by accident. A new addition to our family tree discovered on Luzon Island in the Philippines, Homo luzonensis, between Denisovans & Homo floresiensis, has sparked new research to investigate whether their evolution was accidental or deliberate.
It’s theorised that primitive human relatives fled Africa as far as south-east Asia, crossing the sea to get there. The extinct species remains – a collection of teeth, hands, bones of feet and the femur of a thigh – were found in the Callao Cave, dating back as far as 50,000-67,000 years ago.
Human evolution is just as much by intention as it is by accident
The first of these was found more than 10 years ago, but was then believed to belong to Homo sapiens. It’s thought that they belonged to at least three adults & juveniles. Fingers & toes were curved, indicating that these humans still climbed, akin to a species prior to them – the Australopithecines.
Florent Détroit, from the Natural History Museum in Paris, the first author of last month’s research paper, suggested that the discovery of Homo luzonensis challenges the prevailing theory of human evolution. Ongoing research is working to establish how Homo luzonensis came to be.
Though, we are starting to diverge from the simpler idea of our evolution being a result of humans leaving Africa roughly 1.5 million years back when Homo erectus travelled throughout Africa, Spain, China and Indonesia and our own species followed them some hundreds of years later. There is now evidence supporting the complex hypothesis that we evolved due to the few species that lived alongside Homo sapiens, in combination with interbreeding and extinctions.
So, let’s map out what we know:
1) Homo luzonensis had tiny teeth, indicating that they were small – short of four feet in height
2) These teeth also had a distinctly different size those the rest of the Homo genus.
3) Their curled toe bones suggest that the species were climbers, alike Australopithecines of two or three million years ago.
That leaves the question, why were their feet curled? Perhaps due to adapting to life on the Luzon island when they moved there. But if that’s the case, how did they get to Luzon in the first place if it’s an island that has not previously been connected to any mainland? There’s potential that this was an entirely natural event, such as a tsunami that killed and washed up the three adult and juvenile remains that were found on the Luzon island, or that it was man-made and they arrived there by intention and survived through building a raft or some kind of vehicle to take on the sea. It’s easy to think that Homo erectus simply couldn’t have been intelligent enough to master the sea and move elsewhere. But in the fact that, before, many of them settled on various islands in South-East Asia, we know that their travels were a little more than accidental.
Although attempts to extract luzonensis DNA have thus far been unsuccessful, the dating of the bones & teeth suggest that the luzonensis were around at the same time as the Denisovans, Homo sapiens and Homo floresiensis.